I just finished a quicky backyard sound test. I setup one JBL-15 eon loudspeaker on it's stand, appx. 6 feet off the ground. A CD player and pre-amp were connected to the speaker's input. A tape measure was used to measure distances directly in front of this one speaker, and to the side at a 90 degree angle opposite my RV (forming a wall to me backyard).

Playing music w/ significant bass content (widespread panic: Ball) the volume was turned up until 90dB peaks were measured at 25' (a-weighting, fast response). The meter was held in front of my body at head height, appx. in-line with the speaker output.

I would judge this volume level as "loud" (certainly louder than I could continue here in town at night for long without the police showing up), and sufficient for the average sound camp. People would have difficulty talking without cupping the person's ear they were trying to talk to, or shouting. It was not "chest thumping" loud, however, so dedicated sound camps would most likely desire to go higher than this if able. It did completely fill my backyard with sound. The music was clearly audible at the street, appx. 125' away on the other side of my house.

The sound level measured at the speaker was 108dB at 3 feet (1 meter). This is consistant with expected sound drop-off due to distance (I think I made an error in my post above stating 120dB would be required, relying too much on tables). Most speaker systems would be able to easily reach this level if powered by a 300w amp (assuming minimum of 88dB@1M efficiency), with "commercial" systems capable of playing at least 6-12dB higher at max. volume. using the same amp.

As a quicky test, I also made a measurement 25' away at a 90 degree angle on the other side of the RV; it was only a 70dB peak. This would suggest that solid barriers such as RV's have a significant effect on reducing noise (probably a "duh!" to most people). The volume was audibly "less loud" - conversation would be difficult, but possible. Even a small gap allowed the sound to peak again (between RV and shed, for instance, appx. a 3 foot gap).

While my speaker could go louder (pre-amp volume appx. 1/2 way up), I chose at this time not to do so, in order to prevent angering any neghbors that might be nearby.

In my opinion, the 90dB at 25' standard is a good one, but unlikely to completely satisfy picky neighbors (certainly not ones without earplugs). Wearing earplugs should reduce this level to appx 70dB 25' in front, or 50dB 25 feet to the side opposite a strong wall such as an RV). If one was to try sleeping 25 feet inside your camp, with earplugs, and the speakers were located opposite a strong wall, the level would be appx. 44dB, which in my experience is adequate for sleep to occur (ymmv).

Conclusions;

-bring earplugs for sleep (always a good idea within BRC)
-try to sleep as far inside your camp as possible, and opposite strong walls if a sound camp is next door.
-setup you speakers pointing away from neighbors at least 25' inside your camp, and ideally use strong walls between you and your neighbors.
-most sound systems will require volume control (ie- not cranked up all the way) to meet this standard.

Talent hits a target no one else can hit; Genius hits a target no one else can see.
Arthur Schopenhauer

A-weighting the sound measurement focuses on the "human perception range", and attempts to adjust the measurement to match more closely what humans perceive. Therefore A-weighting is more useful when dealing with human issues.

C-weighting looks at more of the sound scale, without such drastic adjustments (especially in the bass frequencies). Therefore c-weighting is more of an "absolute" method, but may over emphasize some frequencies (like bass) with respect to humans.

Do you agree with "fast" response for measurements (peaks), or should "slow" response be used (more of an average result, as opposed to looking at the peaks)

And I agree with the bass remark re:JBL15eons - they claim a response down to 50hz, but that is probably a -10dB mark. If cranked up, however, they will cause your chest to thump (of course, your ears are close to bleeding by then!) Perhaps next I will repeat the experiment and take a frequency response measurement to qualify how much bass is present...

Which leads to a question I have had for a while, is the 300w "rule" all the amps added up, or just one channel? I would assume all the amps added up, but there might be other opinions.

Talent hits a target no one else can hit; Genius hits a target no one else can see.

Upon checking, my meter has C weighting on the left of the selecter switch, A on the right. I think in alphabetical order, I guess. <duh> hazards of working from memory.

Do you agree with "fast" response for measurements (peaks), or should "slow" response be used (more of an average result, as opposed to looking at the peaks)

Um, depends. <??>

the "fast" will produce higher readings (resulting in more conservative sound levels). I think the slow scale may be a little easier for the average Joe to track -- a skew very dynamic material less. (the standard boom boom that people grumble about is so highly compressed that the slow/fast readings will be very similar.

as far as the 300 watt thing, my vote goes to dropping that spec altogether. Because I believe that sounds systems that aren't overworked *sound* better, I'll vote for 300 watts per band (IE: stereo bi-amp would be 4 300w channels. This puts the responsibility on the operator, rather than the physical limitations of the system to keep volume in line, but it sounds better. ;)

Upon checking, my meter has C weighting on the left of the selecter switch, A on the right. I think in alphabetical order, I guess. <duh> hazards of working from memory.

Do you agree with "fast" response for measurements (peaks), or should "slow" response be used (more of an average result, as opposed to looking at the peaks)

Um, depends. <??>

the "fast" will produce higher readings (resulting in more conservative sound levels). I think the slow scale may be a little easier for the average Joe to track -- a skew very dynamic material less. (the standard boom boom that people grumble about is so highly compressed that the slow/fast readings will be very similar.

as far as the 300 watt thing, my vote goes to dropping that spec altogether. Because I believe that sounds systems that aren't overworked *sound* better, I'll vote for 300 watts per band (IE: stereo bi-amp would be 4 300w channels. This puts the responsibility on the operator, rather than the physical limitations of the system to keep volume in line, but it sounds better.

A great sound engineer is like gold dust. Who combines the irreplaceable skills of taste, precision, technical expertise, patience and a great attitude with top of the range gear and a complete understanding of how to use it effectively

sound engineer "I can't fix it it's on stage." You can’t let a DJ/live musician control the PA sound system that can’t hear what it sounds like in front of the stage. So they turn it up more because it sounds great on stage. That is why sound hurts sometime it can make you sick. Noshes vomit and no not the music the sound waves passing though your body. Some people like this wave and will stand holding on to an 8-foot stack. We had to tell new security in front of stage to not stand in front of the stack. Many a night with bad sound engineers people went home with bad headaches.

Thanks it would be great to take you to a real show with a real theater. Sorry but I watch very little of the show. The last show I just went to have fun was the Rolling Stones in Oakland I think it was the Babylon tour. Spent most of the show at the soundboard I could not see the stage. In luck for me the guy I was with was using his pass to take me all over the show. Spent some time back stage. Man I love the production of a big show.

I like to have the full spectrum. I think that even though the human ear cannot hear it, it still affects the overall quality of the sound. Of course I could be wrong. But that is what I always thought. And yes a good sound engineer is priceless.

Sorry Jafe
back on topic A good book to read about sound "Psychology of Music"By Carl E Seashore

Standard study by founder of Seashore test. Relationship between physical phenomena of sounds and our perception of them. Music as a medium, physical acoustics, auditory apparatus, sound perception, host of other topics.... It has some Amplification of sound —Principles of measurement and guidance.

Thanks it would be great to take you to a real show with a real theater. Sorry but I watch very little of the show. The last show I just went to have fun was the Rolling Stones in Oakland I think it was the Babylon tour. Spent most of the show at the soundboard I could not see the stage. In luck for me the guy I was with was using his pass to take me all over the show. Spent some time back stage. Man I love the production of a big show.

sounds like fun!!! just give me enough time to get my ass across the country.

A great sound engineer is like gold dust. Who combines the irreplaceable skills of taste, precision, technical expertise, patience and a great attitude with top of the range gear and a complete understanding of how to use it effectively[/quote]

Everybody wants to be the lead singer or guitar player. Nobody ever said "fuck being Mick Jagger or Keith Richards, I want to run the SOUND BOARD!". Groupies for the sound guy? Stand in line behind the drummer.

It all starts with high school garage bands.
If you are a cousin of somebody in the band and you own a pick-up truck,
then you get to be the roadie/sound guy. No talent required.
Sad, but oh so true.....

Gizmo wrote:A great sound engineer is like gold dust. Who combines the irreplaceable skills of taste, precision, technical expertise, patience and a great attitude with top of the range gear and a complete understanding of how to use it effectively

Everybody wants to be the lead singer or guitar player. Nobody ever said "fuck being Mick Jagger or Keith Richards, I want to run the SOUND BOARD!". Groupies for the sound guy? Stand in line behind the drummer.

It all starts with high school garage bands. If you are a cousin of somebody in the band and you own a pick-up truck, then you get to be the roadie/sound guy. No talent required. Sad, but oh so true.....[/quote]

I worked with a sound guy that worked as a grip at wood stock. He was just a kid.
There is a picture of him on the album. He would only just say he was one of the kids on there. Someone said on top of a speaker stack I could never find out which one he was. And for the record the Executive Producer gets the best groupies and that is what I choose to be.

Richard Hite, Bear's brother played my house warming party a few years ago. I wish I had pictures. I told them to bring a couple of amps, but they set up the full show with lighting. They kept turning the amps up, but they were so harmonic, the neighbors only had praise.

"Everything is more wonderful when you do it with a car, don't you think?"
-girl by the fire, watching a tree moved by car bumper in the bonfire

It would be a shame if I had to resort to self-deception to preserve my faith in objective reality.